Epson Power Supply S1F70000 User Manual
Page 71
S1F76540 Series
2–28
EPSON
S1F70000 Series
Technical Manual
P
OFF1
P
OFF2
Functions
(High = V
DD
) (High = V
DD
) Oscillator Booster Regulator
Applications
Mode
(Low = V
I
) (Low = V
I
)
circuit
circuit
PS1
High
Low
ON
ON
ON
All circuits are turned on.
PS2
Low
Low
OFF
OFF (
*
1) OFF (
*
2)
All circuits are turned off.
PS3
High
High
OFF
ON
ON
Slave unit side of parallel connection
(Booster and regulator)
PS4
Low
High
ON
ON
OFF
Master unit side of parallel
connection (Booster only)
Power-off Control Function
The S1F76540 has the power-off function and turns on
or off each circuit function when control signals are en-
tered in the P
OFF1
and P
OFF2
pins from an external sys-
tem (such as microprocessor) as defined on Table 2.7.
This power-off function can also cut the reactive current
in parallel connection and other application circuits.
To use the dual-state, power-off control (all ON and all
OFF states) only, connect pin P
OFF2
to pin V
I
and use
only pin P
OFF1
for power-off control.
*
1 When the booster circuit is off, approximately V
I
+ 0.6 V voltage appears at V
O
pin.
*
2 When the regulator is off, the V
REG
pin becomes high-impedance state.
Application notes on power-off function:
• When using external system signals for power-on control, start to control the power only when V
I
voltage
becomes stable after power-on. Unstable V
I
voltage may destroy the IC permanently during on/off control.
Figure 2.6 Start timing of power-off control
Table 2.7 Available combination of power-off control
V
I
P
OFF1
P
OFF2
V
I
P
OFF1
P
OFF2